CA1239526A - Polyhydridosilanes and their conversion to pyropolymers - Google Patents

Abstract

Abstract of the Disclosure A polyhydridosilane has a catenated silicon backbone of 15 to 4000 silicon atoms with an average number of hydrogen atoms per silicon atom in the range of 0.3 to 2.2, at least 0.1 gram of the polyhydridosilane being soluble at 20°C in 100 grams of tetrahydrofuran, toluene, or methylene chloride. The polyhydridosilane can be derivatized or it can be converted to a pyropolymer or a nitrogen-containing pyropolymer which is useful as an abrasive, ceramic, electrical, or electro-optical material.

Description

I

Polyhydridosilanes and Their Conversion to Pyropolymers Field of the Invention The present invention relates to polyhedra-disallowance having catenated silicon backbones, certain 5 derivatives thereof, their conversion to pyropolymers, and methods therefore The pyropolymers are useful, for example, as abrasives, ceramics, and electrical or electro-optical materials.

Back round Art g The unique properties which characterize organic compounds are due not solely to carbon atoms, but rather to the bonding of carbon atoms to each other and to the combination of carbon and hydrogen atoms. Silicon, in the same group of the periodic table as carbon, shares some of the bonding characteristics of carbon and forms analogous catenated structures but has its own unique qualities, namely, generally greater chemical reactivity, and has been the subject of extensive research in recent years.
Catenated silicon systems are known and are reviewed by R. West in G. Wilkinson, FAG Stone, and EYE.
Abel, "Comprehensive Organometallic Chemistry", Volume 2, Chapter 9.4, pages 365-387, Pergamon Press, New York (1982). The silicon-silicon bonds in such systems are most often formed from two silicon-halogen bonds with a Periodic Groups IA or Group IDA metal. Generally, groups such as alkyd, halogen, alkoxy, or aureole are predominantly attached to the catenated silicon backbone.
In contrast to the reported progress in the field of organo-substituted polysilanes, the syntheses of the silicon analogs of the parent carbon polymers such as polyethylene or polypropylene have remained more elusive.
These polymers are classed as silicon hydrides, referred to in this patent application as polyhydridosilanes, and are 3L23~

generally reactive towards the atmosphere and not amenable to preparation and study without manipulation using vacuum line and/or controlled atmosphere (dry box) techniques.
A few examples of catenated silicon systems containing hydrogen atoms attached to a silicon backbone are known. For example, U.S. Patent No. 3,146,248 discloses certain end blocked polysilanes which are useful for rocket propellants and explosives. The preparatory method disclosed requires at least two monomers and one of these can have only one halogen attached to a silicon atom.
Sill derivatives of Periodic Group IA or IDA
metals can be formed from silicon-halogen, silicon alkoxy, silicon-hydride or silicon-silicon bonds, as described in C. Eaborn, "Organosilicon Compounds", Chapter 12, pages 15 357-360, Academic Press, New York (1960). Reaction of catenated silicon systems with alkali metals to give delocalized radical anions has been reviewed by R. West in "Comprehensive Organometallic Chemistry", swooper, pp.
393-395.
In the thermal treatment of polymers wherein cross linking occurs, the resultant materials become stabilized due to the formation of a rigid insoluble network and the stable products are referred to as pyropolymers by S. D. Buck and P. F. Limo (J. Polymer 25 Sat., Part A-l, 8, 771 (1970)).
Formation of elemental silicon by the energetic decomposition of gaseous molecules containing hydrogen and/or halogen and from one to about three silicon atoms is well known and is taught, for example, in U.S. Patent Nos.
4,363,828 and 4,202,928.
Polymeric precursors to elemental silicon are less well known, although perhalopolysilanes are mentioned as precursors in U.S. Patent Nos. 4,374,182 and 4,138,509.
The formation of silicon carbide (as fibers, films, 35 binders, bulk material and the like) by the energetic treatment of polymeric organosilanes is disclosed, for example, in U.S. Patent Nos. 4,310,482 and 4,283,376. As ~,~39~26 U.S. Patent No. 4,289,720 discloses, multivalent elements such as boron, carbon, nitrogen, oxygen and transition metals and the like, which are incorporated into the silicon-containing polymer, are in general also found in the pyropolymer. U.S. Patent No.
4,393,097 describes an amorphous silicon-nitrogen-carbon compost it ion formed by chemical vapor deposition. U.S. Patent No.
4,387,080 describes the heating of a mixture containing silicon, organic silicon polymer, and flaky beta-silicon carbide with gaseous ammonia to give a silicon nitride-containing silicon carbide.
Summary of the Invention Briefly, the present invention provides soluble polyhydridosilanes having catenated silicon backbones having an average of 15 to 4000 silicon atoms with an average number of hydrides (hydrogen) atoms per silicon atom in the range of 0.3 to

2.2. In view of the known high reactivity of hydridosilanes towards air, oxygen, water, and in particular to Periodic Groups IA and IDA metals, it is surprising that the polyhydridosilanes obtained by the method of the present invention are tractable materials which are solids at room temperature and pressure and have the desirable property of being soluble in organic solvents.
The polyhydridosilanes can have use as elastomers, films, fibers, coatings, in composites or articles having utility such as photo resists, adhesives, or surface modifiers.
In another aspect, the chemistry of the Sue bond in these polymers can be exploited e.g., reaction across a carbon-to carbon multiple bond, or reaction with alcohols, amine, or 1~3952~ 60557-2859 organometallic reagents, to give modified or cross linked materials having use as molding compositions, photo resists, and precursors to ceramic materials.
In a further aspect, polymers containing sill derivatives of Periodic Groups IA or IDA metals can be obtained either directly or by treatment of the isolated polyhydridosilanes with Periodic Groups IA or IDA metals.
These are red, air-sensitive materials which are soluble in organic solvents, and which demonstrate chemistry typical of sill derivatives of Periodic Groups IA or IDA metals.
This reactivity, e.g. with amine, alcohols, trio groups, or carbon-to-halogen or transition metal-to-halogen bonds, can be used to give modified materials having utility as molding compositions, photo resists, and precursors to ceramic materials.
In a still further aspect, thermal treatment of the polyhydridosilanes of the present invention provides pyropolymers containing elemental silicon, silicon carbide, and/or carbon in either combined or elemental form and which are high temperature-stable materials. In yet a further aspect, the polyhydridosilane or the pyropolymer can be caused to react with a nitrogen source such as gaseous nitrogen or ammonia at elevated temperatures to form a new pyropolymer which additionally contains silicon nitride or Sin bonds.
In the process of the invention, at least one hydridosilane is polymerized to form a polyhydridosilane wherein each silicon atom in the polymer preferably has at most one R group and O to 2 hydrogen atoms and is connected to 2 or 3 other So atoms such that a valence of four for each silicon atom is maintained and such that the average number of hydrogen atoms per silicon is in the range of 0.3 to 2.2. R can be a hydrogen atom or an aliphatic or aromatic group having up to 25 carbon atoms. A mixture of hydridosilanes can be copolymerized to give polyp hydridosilanes having aliphatic, aromatic, or a combination of aliphatic and aromatic groups in addition to hydrides in the resultant polymer, or a hydridosilane can be copolymerized with sullenness containing no hydrides The process of the invention provides organic solvent-soluble catenated silicon systems containing silicon-hydrogen bonds which can be prepared from sullenness in a one-step process.

lX395Z~

In the prior art, tractable polysilanes were prepared from sullenness, but the resultant polysilanes did not contain silicon-hydrogen bonds, unless they were introduced in subsequent steps. It is believed that the present invention method of preparing tractable polyhydridosilanes having at least 9 catenated silicon atoms and an average in the range of 0.3 to 2.2 hydrogen atoms per silicon atom is novel.
Pyrolyzes of the resulting polyhydrido~ilanes of lo the invention provides l) pyropolymers containing elemental silicon which can be useful in electronic and electron optical applications, 2) pyropolymers containing silicon and silicon carbide which can be useful in electronic, ceramic, and other applications, and 3) pyropolymers containing silicon carbide which can be useful in ceramics and photovoltaics. Further, pyrolyzes in the presence of a nitrogen source results in silicon nitride-containing pyropolymers which may be used as abrasives and ceramics.
In the present invention:
"catenated" means a joined silicon-silicon backbone which can be linear, branched, cyclic, or combinations thereof, and the valence of each silicon atom is four;
"oligomer" means a compound containing 2, 3, or 4 monomer units;
"polymer" means a compound containing more than 4 monomer units;
"film-forming" means sufficiently soluble in a common volatile organic solvent such as Tulane, twitter-hydrofuran, or dichloromethane to enable a coating to redeposited by conventional coating techniques such as knife coating or bar coating; generally, a volubility of polyhydridosilane as low as 0.1 gram in 100 grams of organic solvent at 20C is useful, although a volubility of at least l gram is preferred;
"silicon hydrides or "hydrides" means a hydrogen atom which is bonded directly to a silicon atom, -6- ~23~26 "sill derivative of Periodic Groups IA and IDA"
means a compound containing a silicon atom bonded to three groups preferably selected from hydrogen, aliphatic or aromatic group, or another silicon atom and containing a silicon-to-rnetal bond where the metal is a Periodic Group IA or IDA metal;
"Solon" means a compound having the formula Swahili where each of Al to A may be chosen from alkyd, alkenyl, aureole, halogen, alkoxy, hydrogen or other radicals such as amino, cyan, and Marquette, "hydridosilane" refers to a Solon where at least one of Al to A is hydrogen;
"polysilane" means a polymer containing a catenated silicon backbone with other atoms or groups pendant such as hydrogen, halogen, silicon, organic groups (optionally including hotter atoms), Periodic Group IA or IDA metals, or inorgano- or organometallic groups, such that each silicon maintains a valence of 4;
"polyhydridosilane" means polymers resulting from polymerization of at least one hydridosilane and having catenated backbones with an average number of hydrides atoms per silicon atom in the range of 0.3 to 2.2;
"single bond connecting two silicon atoms" means that a single bond attaches a catenated silicon atom of one polymeric backbone to a silicon atom which may be on another polymeric backbone so as to effect a branch-point, cross link, or cyclic structure in the resulting polymeric chain;
"substantially cross linked" means a three-dimensional polymeric network wherein the resultant polymers no longer soluble;
"soluble" means that a finite amount of a compound can be dissolved in a particular solvent to give a solution i.e., the solution contains at least 0.1 gram of polyhydridosilane, and preferably 1.0 gram, dissolved in 100 grams of organic solvent such as tetrahydrofuran, Tulane, ethylene chloride, etc. at 20C, or in the case 3L~39~

of a dispersion it will pass through a lo to 15 micrometer frilled glass filter medium;
"tractable" means having properties such as volubility, volatility and/or extrudability to an extent that allows study and processing;
"pyropolymer" means a stable polymer produced by thermal treatment of polymers wherein cross linking occurs:
"catenary" means in the backbone, not a terminal or pendant group;
"elemental carbon" means any of the allotropic forms of carbon; and "organometallic group" means a group containing carbon to metal bond.

Detailed Description The present invention comprises a polymer having a backbone comprising repeating monomeric units having the formula:

R
So I
R

wherein all R's may be the same or different and are independently selected from the group consisting of 1) hydrogen, 2) a linear, 25branched, or cyclic aliphatic group (preferably alkyd or alkeny~) having 1 to 10 carbon atoms and optionally containing at least one Periodic Group VA or VIA
atom which is preferably selected from oxygen and nitrogen, 3) an aromatic group [preferably aureole, aralkyl, or alkaryl group (wherein aureole preferably is a sin-glue ring, such as phenol, bouncily, toll, or a fused ring, such as naphthyl)], all 526 owe of these groups optionally substituted by up to three Of to Coo linear, branched, or cyclic aliphatic group said aromatic or aliphatic wrap optionally containing at least one Periodic Group VA or VIA
atom which preferably it selected from oxygen and nitrogen, the total number of carbon atoms being up to 25, 4) a jingle bond connecting two silicon atom, 5) a metal atom selected from the group consisting of Periodic Group IA and IT
and 6) an inorgano- or organometallic group comprising at least one Periodic Group IT to VIIB, VIII, and Lanthanide and Astound element;
wherein the ratio of hydrides to silicon is in the range of 0.3 to 2.2; and the average number of monomeric units in the polymer it in the range of 15 to 4000.

R can be an aliphatic or aromatic group capable of forming one or more bond to one or more silicon atoms which group optionally can contain at least one atom of N, P, As, Sub, Bit 0, So Sex and To. These heteroatoms may or may not be bonded directly to a silicon atom which it part of a catenated system, e.g., alkoxy such a -Ouzel, arylalkylamino such as -N(CH3)(C6HsCH2)/ ether (catenary oxygen) such a -(CH2)2-0-CH3, arylthio such as -SKYE), and alkylpho~phino such as -P(C2Hs)2. Preferred R groups include hydrogen, methyl, ethyl, n-butyl, methoxy, phenol, bouncily, benzylmethylamino, phenethyl, silicon, lithium, dummy, and iron (dicarbonyl)cyclopentadienyl.
The polymers of the invention, wherein the monomeric units may be randomly arranged, are film-forming and soluble in common organic solvents, have catenated silicon backbones, and are commonly referred to as polyp lZ3~t52~, hydridosilanes. They are also referred to in the art as polyp silylenes and polysilanes. Polyhydridosilanes may have utility as precursors to pyropolymers~ The polyhydridosilanes can be coated as films, drawn into fibers, or utilized in bulk or as binders before pyrolyzes.
Polyhydridosi]anes of formula I, wherein n has an average value in the range of 15 to 4000, preferably 15 to 2000 and most preferably 20 to 1000, have average molecular weights in the range of 350 to 500,000. Lower molecular weight polyp hydridosilanes, i.e., where n has an average value of 9 to Abbott, are liquids with high vapor pressures. They are more difficult to handle in air (i.e., they readily oxidize) than higher molecular weight polyhydridosilanes but they may be preferred in applications where appreciable volatility is desirable.
Hydridosilane monomers alone or in the presence of organosilanes polymerize in the method of the invention in one step to polyhydridosilanes. Polyhydridosilanes can be prepared by 1. providing a suitable hydridosilane having the general structure HER Sioux, where R is as defined above for R groups 1) to 4), except that R groups chosen from R groups 2) to 4) must be sufficiently stable so as to be unreactive under the conditions of the reaction (preferably only catenary oxygen is present as a heteroatom), and wherein the hydridosilane preferably contains at most one aliphatic or aromatic group per silicon atom, and X
is a halogen atom, preferably chlorine, and -pa- 60557-2859 2. reacting the hydridosilane above with a suitable Periodic Group IA (alkali) or Group IDA (alkaline earth) metal or alloy in an amount of at least 1 equivalent of metal per equivalent of halogen in an inert atmosphere Jo 10- ~3~26 such as argon or nitrogen and in an inert delineate such as tetrahydrofuran or Tulane for a period of time sufficient to provide the desired polyhydridosilane.
Preparation of polyhydridosilanes according to the present invention may be illustrated by the following equation (1) (for a Group IA metal) Al (Rl)2SiX2 + M (excess) - Jo + MY (1) Al where Al is as defined above, and M is a Periodic Group IA
or Group IDA metal or alloy. X is preferably chlorine but may be another halogen such as bromide or iodine or a combination of halogens. The monomeric units shown in equation 1 are repeating and may be randomly arranged in any proportion. There are from 9 to 4000 monomeric units in each polymer, preferably 12 to 4000, and most preferably 15 to OWE units. The silicon-hydride bonds are not completely inert to the reaction conditions, and some of them react to form Swiss bonds, with a hydrides to silicon ratio in the range of 0.3 to 2.2. The positions along the catenated silicon backbone where the hydrides has reacted contain silicon atoms bonded to three or four other silicons, so that a valence of four is maintained and may be branch points, parts of a cyclic structure or cross links. When one Al is selected from aliphatic or aromatic groups the Rl-Si bond is inert to the reaction conditions, and thus each silicon in the polymer will be bonded to two or three other silicons, one Al and zero or one H. When one Al is hydrogen, the Rl-Si bond is no longer inert to the reaction conditions, and each silicon atom may now be bonded to two, three or four other silicon atoms and two, one or no H atoms, such that a valence of four is maintained for each silicon atom.

-l 1- 1~39~
Examples of hydridosilanes ~I(Rl)SiX2 which may be used as starting materials in the present invention include methyldichlorosilane, ethyldichlorosilane, phenyldichloro-Solon, dichlorosilane, and the like. The invention is not intended to be limited to these particular starting material sullenness.
The polymers of the invention are soluble in organic solvents such as tetrahydrofuran, Tulane, ethylene chloride and the like, forming solutions of at least 0.1 gram in lo grams of organic solvent and preferably 1.0 gram per 100 grams of solvent. Many of the polymers are even more soluble than that, and solutions of 10 grams or more per 100 grams of organic solvent can be obtained. This distinguishes them from materials of similar composition in the prior art, in that those materials are insoluble. Volubility is a desirable property, in that it allows convenient study and handling of these materials. Those skilled in the art will appreciate that this property can allow the polymers to be cast into films and fibers, further modified chemically in homogeneous reactions, conveniently analyzed, or otherwise manipulated or formed.
The polyhydridosilanes of the invention are white or pale yellow, and may be transparent or translucent or opaque. They may be air-sensitive or stable in air, depending on the substituents R; generally, electron-with-drawing groups R yield a material which is more air-stable than those materials with electron-donating groups.
Copolymers of hydridosilanes can be prepared by the reaction of a mixture of different hydridosilanes with a suitable metal. For example, an aliphatic-substituted hydridosilane with an aromatic-substituted hydridosilane can be caused to react with a metal such as sodium to yield a random copolymer comprised of randomly repeating units of an alkyl-substituted hydridosilane with randomly repeating units of an aureole substituted hydridosilane. This reaction may be exemplified by the general equation (Rl)2SiX2 + (R2)2SiX2 + Mixes) - > s sly + MY (2) where R1 and R2 may be the same or different and are independently selected from R groups 1), 2), 3), and 4), and M, and X all are as defined and restricted above, and Al and R2 are not all alike. The monomeric units shown in equation 2 may be randomly arrayed, and there are from 9 to 4000, preferably 12 to 4000, most preferably 15 to ~00 monomeric units in each polymer. As was described above, the Sigh bonds are not inert to the reaction conditions, and the polymer contains a hydrides to silicon ratio of from 0.3 to 2.2, with a valence of four being maintained for each silicon atom. Hydridosilanes may also be copolymerized in a similar manner with sullenness containing no hydrogen on the silicon atoms. The metal with which the hydridosilane is treated may be a Group IA metal such as lithium, sodium, potassium or alloys or combinations thereof or a Group IDA metal such as magnesium which will reduce silicon-halogen bonds. At least one metal equivalent per equivalent of halide is used. A temperature in the range of -78 to 150C can be utilized. Other reducing conditions and techniques, such as electrolysis, are also suitable. Reaction times are sufficient, depending on temperature, to allow the silicon-halogen bonds to react and form the polyhydridosilane.
Equations 1 and 2 are intended only as examples, and it is not intended that the invention be limited to these particular combinations.
Reactions of the present invention can proceed readily under mild conditions (i.e., -78 to 40C) without the necessity of using elevated temperatures. As with any reaction involving the use of alkali metals and/or silicon halides, the reaction is performed under an hydrous conditions in the absence of reactive oxygen in an inert atmosphere, such as nitrogen or argon.

I

The reaction may be carried out in any suitable solvent or vehicle which does not adversely affect the reactants or products, and tetrahydrofuran as solvent is particularly suitable. Other solvents which are suitable and in which the resultant colorless or lightly colored polyhydridosilanes are soluble are 1,2-dimethoxyethane (glum), and Tulane.
Useful catalysts to increase the rate of reaction of hydridosilanes with the previously mentioned metals include naphthalene and other polynuclear aromatics. In the case where a dihydridosilane is used, naphthalene as catalyst is particular desirable because it allows the reaction to proceed under very controlled conditions (i.e., temperatures in the range of -78 to -40C) which avoids formation of a substantial number of cross links and the production of insoluble materials. A stoichiometric amount of catalyst can be used, but preferably an amount in the range of 0.01 to 5 0 mole percent per hydrosilane compound and most preferably 0.1 to 1.0 mole percent is employed.
Upon mixing of a hydridosilane and a Periodic Group IA or IDA metal, or combinations or alloys thereof, an exotherm is observed. The resulting polyhydridosilanes, which are the precursors to the pyropolymers of the invention, can then be isolated and stored as long as they are kept free from moisture and oxygen, i.e., they are kept in an inert atmosphere in the absence of light at 25C or less. The polyhydridosilanes are soluble in common organic solvents such as Tulane, tetrahydrofuran, glum, and dichloromethane.
In another aspect of the invention, sill derivatives of Periodic Groups IA and Group IDA metals may be formed from Six (where X = halogen), Sue, Swiss or catenated silicon systems by several mechanisms. Under appropriate reaction conditions (preferably, sufficient reaction time in the presence of a sufficient quantity of Periodic Groups IA or IDA metal M, preferably sodium, potassium, lithium, or magnesium), a polymer containing ~Z3~35~g~

sill derivatives of metals M may be obtained in a one-step synthesis using more than 1 equivalent of metal per equivalent of halogen. Alternatively, one can allow polyhydridosilanes of formula I to react with M metals in an amount of 0.01 to 5 equivalents of metal per equivalent of hydrides in an appropriate solvent under inert atmosphere and obtain sill derivatives of the metal in this manner.
Materials prepared by either method demonstrate the reactivity expected of silyl-M compounds such as reaction with an aliphatic or aromatic halide or a transition metal halide complex:

(Rl)3Si-M+ + R3C-X > (Rl)3Si-CR3 + MY (3) (Rl)3Si M+ + TXnLm > (Rl)3Si-TX(n-l)Lm + MY (4) (Rl)3Si-M+ + Curl - > (Rl)3Si-Si(Rl)3 + Cut + Mel (5) where R, Al, M and X are as defined above. A transition metal halide complex is represented by TXnLm where T can be selected from one or more of Tip Or, Hi, V, Nub, Tax Or, Mow W, My, Rev Fe, Rut Ox, Co, Rho If, Nix Pod, Pi, or Astound or Lanthanide metal, X can be a halogen (Clue Bra or I), n can be an integer from one to five; L can be independently selected from one or more of the following groups: 1) an aliphatic or aromatic group containing one or more carbon-to-carbon multiple bonds such as ethylene, diphenyl-acetylene, Bunsen, cyclooctadiene, cyclopentadienyl, and Tulane, 2) a group containing one or more Periodic Group VA atoms optionally substituted with up to 4 groups independently selected from aliphatic and aromatic, and a hydrogen atom, such as ammonia, trimethylamine, triphenyl-phosphine, trimethylphosphine, dimethylphenylphosphine, tetramethylammonium, triphenylarsine, and 1~2-bis(diphenylphosphino)ethane; or the Group VA atom or atoms may be part of an aromatic group, such as pardon or 2,2'-bipyridyl, or the Group VA atom may be multiply bonded -15- ~3~26 to carbon and optionally substituted with at least one aliphatic or aromatic group, such as cyan, acetonitrile, or t-butylisocyanide; 3) a group containing one or more Group VIA atoms optionally substituted by up to 5 groups independently selected from aliphatic and aromatic groups, or a hydrogen atom, such as tetrahydrofuran (THY) or, the Group VIA atom(s) may be multiply bonded to carbon and optionally substituted with at least one aliphatic or aromatic group, such as acetylacetonate, 4) Al, where Al is as defined above, such as Cell, t-butyl, or phenol 5) CO;
and wherein m is selected depending on L so as to achieve a stable compound, generally, an 18 electron configuration, or for metals such as Rho If, Nix Pod, and Pi, a 16 electron configuration may be stable. Generally, m can be an integer in the range of 1 to 6.
Examples of stable inorgano- and organometallic compounds are:
l) (Cp)2TX2, where T can be Tip Or, Hi; X can be C1 or Bra and Cup = cyclopentadienyl;
2) CpT(CO)px~ where T can be Or, Mow W, where pi and X
can be C1 or Bra or T can be Fe, Rut Ox, where pi and X
can be Of or Bra

3) [(Rl)3P]2TX2 or [(R1)3P]2TX(Rl), where T can be Nix Pod, Pi, and X can be C1, Bra or I;

4) CpT(CO)X2 or CpT(CO)X(R1) where T can be Co or Rho X
can be Of;

5) [Cs(CH3)l0]2TX, where T can be Lug or Y;

6) (NH3)2PtC12; (CO)qTX~ where T can be Co, Rho or If; q=4 and X can be Of or Bra or where T can be My or Rev q=5, and X can be Of or Bra (Cortex, where T can be Fe, Rut Ox, r=4, and X can be C1 or Bra Other suitable compounds may be found in many reference on inorgano- or organometallic chemistry. In Equations 3, 4 and 5 above, one or more ox R is a single bond connecting two silicon atoms, so that R3Si~Na+ represents part of the polyhydridosilane-containing sill derivative of Periodic Groups IA or IDA.

-16- ~.23~5~
The polyhydridosilanes derivatized with Periodic Groups IA or IDA metals remain reactive for long periods of time, so long as they are protected from moisture or other reagents, that is, as long as they are stored under inert atmosphere. Monomeric units, for example, having the formula ( + 3 wherein Al and M are as defined above, are present in the polymer and under appropriate conditions remain active and have the capability of reacting with groups such as alkyd halides, transition metal halides, or an oxidizing agent such as copper (I) chloride. It is not intended that the invention be limited to these particular examples of silyl-M reactivity.
In a further aspect of the invention, the Sigh bond in the polyhydridosilanes described by formula I may be further reacted with reagents other than Periodic Groups IA or IDA metals. The following examples illustrate this reactivity:

polyhydridosilane with an alcohol:
(Rl)3Si-H + ROW > (Rl)3SioR + Ho (6) polyhydridosilane with an amine:
(Rl)3Si-ll + R2NH (Rl)3Si-NR2 + Ho ( ) polyhydridosilane with an alkene l ) Sue + R2C=CR2 Y ( Al ) 3Si-CR2-CR2-H ( 8 ) (Al ) Sue + R2C=CR2 catalyst> substantially cross linked network (9) R3Si-H + R2C=CR2 photolysis~ substantially cross linked network (lo) I

polyhydridosilane with an inorgano- or organometallic Periodic Group IA or IDA compound:

(Rl)3Si-Si(Rl)3 + M-R2 (Rl)2(R2)Si-Si(Rl)3 + (Rl)3Si-M+ (11) In equations 6, 7, 8, 9 and lo R, Al, R2, and M
are as defined above (and chosen so that (Rl)3Si-H
represents part of the polyhydridosilane). In equations 9 and lo at least one of R is chosen so that R2C=CR2 represents a polyfunctional compound such as divinylbenzene. Other polyfunctional compounds containing groups selected from alcohols, amine, and alikeness, such as ethylene glycol, ethylenediamine, ethanol amine, and diallylamine, are also suitable for forming substantially cross linked networks.
The polyhydridosilanes and derivatives thereof of the present invention may contain a variety of reactive sites, such as Sigh bonds, Swiss bonds and Sir bonds (depending on R), and others (for example, when R =
alkenyl). Those skilled in the art will realize that under certain reaction conditions, the polyhydridosilanes may demonstrate more than one type of reactivity, that is, that two or more reactions may occur at different reactive sites under a certain set of conditions. Such multiple reactivity may be represented, for example, in Equations lo and 11 (where the proportions of each of the several reactions may vary). Multiple reactivity may be desirable in certain applications.
These examples are meant to serve as illustration only, and the invention is not intended to be limited to these particular reactions of Sigh bonds.
In accordance with the present invention, pyrolyzes of the polyhydridosilanes of formula I above, or their derivatives as disclosed above, preferably in a vacuum or in an inert atmosphere, yields pyropolymers, which, depending on the composition of the polyhydrido-Solon and on pyrolyzes conditions, contain at least one of ~23~ 6 silicon, silicon carbide, or carbon. Other multivalent elements, such as transition metals, oxygen and nitrogen, may be incorporated by selecting a suitably derivatized polyhydridosilane~ Varying the pyrolyzes conditions also results in variation in the molecular weight of the pyropolymers due to changes in cross linking. Pyrolyzes conditions determine, to some extent, the degree of crystallinity of the resulting pyropolymer.
In another aspect of the present invention the polyhydridosilane or pyropolymer may be pyrolyzed in the presence of a gaseous nitrogen source, such as ammonia, and under appropriate conditions silicon nitride may result.
Pyrolyzes of the aforementioned polyhydrido-sullenness is conducted over a temperature range of 200 to 2000C, preferably 600 to 1600C, in an inert atmosphere such as argon or in a vacuum until the pyropolymer having the desired properties is formed. If it is desired to prepare a silicon nitride containing pyropolymer, a nitrogen source, such as gaseous ammonia, nitrogen, hydrazine, methyl amine, or ammonium halide is subsequently introduced over a temperature range of 700-2000C. If more crystallinity is desired, higher pyrolyzes temperatures and longer times are utilized.
Generally, pyrolyzes is not observed below 200C
and a practical upper temperature is 1600C. Above 1200C, morphological changes to the more crystalline forms of silicon, silicon carbide, silicon nitride, and carbon (graphite) can be anticipated.
The physical and chemical character of the pyropolymer obtained is dependent upon the form and composition of the polyhydridosilane or copolymeric polyhydridosilane, the temperature of pyrolyzes, and whether a gaseous nitrogen source is used during pyrolyzes.
Polyhydridosilanes as films, fibers, bulk samples, and articles can be pyrolyzed to prepare pyropolymers which can be films, fibers, bulk samples or articles. The Sigh ratio increases with increasing temperature.

-19- 1239~i~6 Pyropolymers find use, depending on their compost-lion, in a variety of applications. Silicon carbide-containing pyropolymers, for example, are used as ceramic materials and as abrasives, and silicon-containing pyropolymers find use as photo conductive materials. Silicon nitride-containing pyropolymers are useful as abrasives and structural ceramics. Other uses of pyropolymers may be apparent to those skilled in the art and are not limited to those uses stated herein.
As mentioned above, the polyhydridosilanes of the invention (prior to pyrolyzes) are useful as films, fibers, or articles in applications such as photo resists, coatings, and composites for modification of surfaces, as elastomers or adhesives, as well as precursors for pyropolymers.
Objects and advantages of this invention are further illustrated by the following examples, but the particular materials and amounts thereof recited in these examples, as well as other conditions and details, should not be construed to unduly limit this invention. In all cases each silicon atom has a valence of four. Where a hydrogen, an aliphatic, or an aromatic group or other group is not indicated, the valence is completed by bonding to one or more other silicon atom or atoms, as required.

This example illustrates the preparation of poly(phenylhydridosilane). The entire preparation was conducted in an inert atmosphere of nitrogen unless indicated otherwise.
To seven grams of a magnetically stirred mixture of mineral oil-free sodium dispersion (from Alga Products, Vent Ron Division of Thickly Corp., Dangers, MA) washed free of mineral oil with dry, oxygen-free hexanes in a nitrogen atmosphere, and covered with 150 ml of dry, oxygen-free tetrahydrofuran (THY), 20 ml of phenyldichlorosilane (Petrarcil Systems, Inc., Bristol, PA) (the Solon was vacuum-distilled before use) was added drops over 1.5 his. at ambient temperature (about 20C). The product was stirred for three days and the resultant red mixture was filtered to remove excess sodium dispersion and Nail. To the filtrate was added 5 g of copper (I) chloride and the mixture was magnetically stirred for one day. The now yellow solution was filtered and tetrahydrofuran (THY) was removed under reduced pressure from the filtrate to leave 10.9 g of pale yellow solid polymer. Spectroscopic analysis indicated the composition of the solid to have the following formula:

[Si(C6H5)H]0,51[Si(c6H5)]o~49 so that a valence of four is maintained. This polymer was handled briefly in air as a solid without significant change.

This example illustrates the preparation of poly(methylhydridosilane) following the procedure outlined in EXAMPLE 1.
To 10 g of a magnetically stirred and mineral oil-free sodium dispersion covered with 150 ml of THY was added drops at room temperature over 2 his. 20.8 ml of vacuum-transferred methyldichlorosilane (Tetrarch Systems, Inc.). The reaction mixture was stirred for four days at about 20C and filtered in a nitrogen atmosphere. Removal of solvent from the filtrate left 4.7 g of pale yellow solid. Spectroscopic analysis indicated the solid corresponded to the composition [Si(CH3)H]0~36(si(cH3)]o~64 This polymer reacted readily with air, with the formation of silo bonds.

-21~ 5~3 This example illustrates the preparation of a random copolymer of an alkylhydridosilane with an arylhydridosilane following the procedure outlined in EXAMPLE 1.
To a magnetically stirred mixture of 1.61 g of mineral oil-free sodium dispersion covered with 50 ml of THY was added drops over 15 minutes at about 20C a solution of 1.73 g of purified methyldichlorosilane and 2.65 g of purified phenyldichlorosilane in 5 ml of THY.
The product was stirred at about 20C for two days and processed according to the procedure in EXAMPLE 2. Removal of solvent from the filtrate left 1.8 g of pale yellow solid polymer. Spectroscopic analysis indicated the solid corresponded to the composition:

[Si(CH3)H]o~22[si(cH3)]o~4[si(c6H5)H]o~37[si(c6H5)oily This polymer was handled briefly in air as a solid, without significant change.
The copolymer was heated under nitrogen at 10C
Manuel from ambient to 1000C. Minor weight loss began at 160C. The main thermogravimetric change occurred in the 240-480C region and was complete by 540C. Total weight loss was about 50 percent, in contrast to the report by Yajima et at. So Patent No. 4,283,376) who show a nearly complete weight loss of poly(dimethylsilane) under similar conditions.

This example illustrates the preparation of poly(hydridosilane) following the procedure outlined in EXAMPLE 1.
Sodium metal (23 g, cut into about twenty pieces) was covered with 600 ml of THY and 100 my of naphthalene was added. The green color typical of sodium naphthalide soon formed. The sodium-containing mixture was cooled by 35~

means of an external liquid nitrogen bath and 27 ml of dichlorosilane (Tetrarch Systems Inc., vacuum transferred from 0C) was condensed into the frozen sodium mixture. It was then warmed to -40C and maintained at -40C for about four days. The reaction mixture was then warmed to ambient temperature and promptly filtered under nitrogen. Removal of solvent from the filtrate left a gummy white solid which was mixed with 300 ml of Tulane to dissolve the polymer.
The resultant mixture was filtered and the Tulane was removed under vacuum from the filtrate to leave 0.7 g of a cream colored solid poly(dihydridosilane) whose spectra-scopic analyses indicated the presence of a silicon to hydrogen ratio of 1 to 1.9 and confirmed the presence of Sue groups. This polymer reacted readily but not violently with air.

NOTE: Dichlorosilane is a highly reactive gas and may contain Sue, which reacts explosively with air.
Additionally, storage of the polysilane Swahili on in the presence of impurities may result in disproportionation and formation of Sue. Appropriate precautions should therefore be observed throughout these procedures.

This example illustrates the preparation of poly(ethylhydridosilane) following the procedure outlined in EXAMPLE 1.
To 10.0 g of sodium (cut into about ten pieces) covered with 250 ml of THY, and containing 90 my of naphthalene, and cooled with an external liquid nitrogen bath was added by vacuum transfer 10.0 g of ethyldichloro-Solon (Tetrarch Systems, Inc.). The reaction mixture was warmed to about 20C, stirred for 3 days at about that temperature, and filtered in a nitrogen atmosphere. Solvent was removed from the filtrate under vacuum to yield 2.90 g of pale yellow oil. Spectroscopic analysis indicated the oil corresponded to the composition [Si(C2H5)H]0.79[si(c2H5)]~2 This polymer reacted readily with air.

This example illustrates the preparation of a random copolymer of a dialkylsilane and a dihydridosilane following the procedure outlined in EXAMPLE 1.
To a flask containing 11.5 9 of sodium (cut into approximately 10 pieces), 100 my of naphthalene, and 250 ml of THY and cooled in liquid nitrogen as in EXAMPLE 4 was added 8.3 ml of purified dichlorosilane and 12.1 ml of purified dimethyldichlorosilane (Tetrarch Systems Inc.).
The mixture was warmed to -40C and maintained at that temperature for one week. It was then warmed to room temperature, and promptly filtered in a nitrogen atmosphere. Removal of solvent from the filtrate gave 2.2 9 of viscous cream-colored oil. Spectroscopic analyses indicated the oil corresponded to the composition:

[Si(CH3)2]0.36[(SiH)(siH2)]0.64 and confirmed the presence of (Sue) groups.
This polymer reacted readily with air.

This example illustrates the preparation of a random copolymer of an alkylarylsilane and an arylhydridosilane following the procedure outlined in To a flask containing 4.7 9 of sodium (cut into approximately 5 pieces) and 50 ml of THY was added drops over 5 mix a mixture of 7.3 9 of phenyldichlorosilane and

7.3 9 of phenylmethyldichlorosilane (Tetrarch Systems, Inc., Bristol, PA) (both sullenness were vacuum-distilled before use) at ambient temperature (about 20C). The reaction mixture was stirred for 8 days, and the resultant red solution was filtered to remove excess sodium and Nail.
The deep red filtrate was placed over 7.4 g of Curl, and stirred overnight. The mixture was then filtered to remove excess Curl, Cut and Nail, and Tell was removed from the filtrate under vacuum to give 8.0 g of pale yellow polymer.
Spectroscopic analysis indicated the solid corresponded to the composition:

[Seiko) (cH3)]o~55[si(c6l~5)H]o~38[si(c6H5]o~o7 This polymer was handled briefly in air as a solid, without significant change.
This polymer was further fractionated by the following procedure: 8.0 g of polymer was dissolved in approximately 15 ml of Tulane, and added drops to 200 ml of hexanes, with stirring. A white powder formed, which was collected by filtration to give 0.9 g of a white solid polymer. The solvent was removed from the filtrate to give 6.6 g of very gummy pale yellow polymer.

This example illustrates the preparation in one step of poly(phenylhydridosilane) containing a sill derivative of sodium following the procedure outlined in EXAMPLE 1.
To 2.5 g of sodium, cut into approximately five pieces and covered with 75 ml of THY, 12.2 g of phenyldichlorosilane was added drops over several minutes. The reaction mixture was stirred for four days until a deep red solution formed. The reaction mixture was filtered to remove excess sodium and Nail, and THY was removed from the filtrate under vacuum to give 7.2 g of deep red solid polymer. Spectroscopic and elemental analyses confirmed the composition of the solid to have the following composition:

[Si(C6H5)H]o.4o[si(c6H5)]o~6o[Na]o~l7 ~23~

This polymer reacted readily with air, although it was stable for months when stored as a solid under an inert atmosphere.

This example illustrates the preparation in one step of poly(methylhydridosilane) containing a sill derivative of sodium following the procedure outlined in EXAMPLE lo To lo g of sodium covered with 150 ml THY, 23 g of methyldichlorosilane was added drops at ambient temperature over 2 hr. The reaction mixture was stirred for five days at about 20C when a deep red solution had formed. The reaction mixture was filtered through a fine porosity glass fruit (4-8 micrometers, dried at 120DC and placed in an inert atmosphere while hot) to remove excess sodium and Nail, and THY was removed from the filtrate under vacuum to give 6.6 g of a deep red solid polymer.
Spectroscopic and elemental analyses confirmed the solid to have the following composition:

[Si(CH3)H]0,25[Si(CH3)]0.75[Na]O.10 This polymer reacted readily with air, although it was stable for months when stored as a solid under an inert atmosphere.

EXAMPLE lo This example illustrates the preparation of a copolymer of an alkylarylsilane and an arylhydridosilane containing a sill derivative of sodium in one step following the procedure outlined in EXAMPLE 1.
To a flask containing 3.7 g of sodium (cut into approximately 4 pieces) and 50 ml of THY was added drops over 5 ruin a mixture of 5.7 g of phenyldichlorosilane and 6.1 g of phenylmethyldichlorosilane at ambient temperature (about 20C). The reaction mixture was stirred for eight ~L2~ri~

days, and the resultant red solution was filtered to remove Nail and excess sodium. Solvent was removed from the filtrate under vacuum to give 6.2 g of deep red solid.
This material was dissolved in 15 ml of Tulane and 5 precipitated into 250 ml of stirred hexanes, to produce 2.3 g of bright yellow powder. Subsequent reactions and spectroscopic analyses indicated the solid corresponded to a composition containing 5 mole percent sill derivative of sodium.

This example illustrates the preparation of a random copolymer of an alkylarylsilane and an arylhydridosilane containing a sill derivative of sodium in two steps following the procedure outlined in EXAMPLE 1.
First, 4.6 g of phenyldichlorosilane and 5.0 g of phenylmethyldichlorosilane were reacted with 3.0 g of sodium (cut into about 3 pieces) in 40 ml of THY, filtered, treated with 3.1 g of Curl and filtered to produce a pale yellow filtrate containing a random copolymer of phenylmethylsilane and phenylhydridosilane as in EXAMPLE 7.
Second, the solvent was not removed from the polymer, but the filtrate was placed over 1.8 g of sodium, and the solution began to turn red within minutes. The reaction mixture was stirred for approximately 3 hours, then allowed to stand for 20 hours. The reaction mixture was filtered, and solvent removed under vacuum to produce 5.1 g of deep red solid polymer. This was further treated by dissolution in 15 ml of Tulane and precipitation into well-stirred hexanes (200 ml) to produce 3.3 g of bright yellow powder.
This was collected by filtration and dried under vacuum.
Subsequent reactions and spectroscopic analyses indicated the solid corresponded to a composition containing approximately 8 mole percent sill derivative of sodium.

This example illustrates the reaction of a polyhydridosilane containing a sill derivative of sodium with a compound containing a carbon-halogen bond.
To 135 my of poly[(phenylmethylsilane)(phenyl hydridosilane)] containing a sill derivative of sodium prepared as in EXAMPLE 10 and dissolved in 0.5 ml of benzene-d6 (Aldrich Chemical Co., Milwaukee, WI) was added

8 micro liters of bouncily chloride. The red color of the sill derivative of sodium disappeared immediately, and spectroscopic analyses indicated the presence of Si-(CH2C6Hs) groups in the polymer. In this particular reaction, some deuterium was also incorporated into the polymer.
In a similar reaction using the polyhydridosilane containing sill derivative of sodium (prepared as in EXAMPLE 11) suspended in hexanes and treated with bouncily chloride, Si-(CH2C6H5) groups were again formed but no evidence of reaction with solvent was obtained.

This example illustrates the reaction of a polyp hydridosilane with an alkene in the presence of a platinum complex known to be a hydrosilation catalyst.
95 my of poly(phenylhydridosilane) prepared as in EXAMPLE 1 was placed in 300 my of benzene-d6 with 180 my of styrenes and 1 my of H2PtC16. Within 24 ho of reaction spectroscopic analyses indicated the presence of SiCH2CH2(C6EIs) groups as well as some unrequited Sigh bonds This example illustrates the reaction of a polyhydridosilane with a polyalkene in the presence of a platinum complex known to be a hydrosilation catalyst to form a highly cross linked network.
0.31 g of poly(phenylhydridosilane) (prepared as in EXAMPLE 1) was dissolved in 0.21 g divinylbenzene to ~23~5~

form a very viscous mixture. 5 micro liters of a solution containing 15 weight percent of a platinum complex with symmetrical divinyltetramethyldisiloxane was added. Within 24 ho of reaction, the sample was very hard and brittle. A
control sample containing no platinum catalyst was still very soft.

This example illustrates the reaction of a lo polyhydridosilane with an alcohol.
100 my of poly(phenylhydridosilane) prepared as in EXAMPLE 1 was placed in 1 ml of Tulane, and 32 micro liters of dry methanol was added. No reaction occurred. 1 my of sodium metal was added as catalyst and within minutes of reaction spectroscopic analyses indicated the presence of Swish groups, and some unrequited Sigh bonds.
In another sample, 100 my of poly(phenylhydridosilane) and 10 micro liters of dry methanol were placed in 1 ml of THIEF and 6 my of 5 weight percent platinum on charcoal was added as catalyst. Within I ho of reaction, spectroscopic analyses indicated the presence of Seiko groups, and some unrequited Sigh bonds.
If a large excess of alcohol is present and under appropriate reaction conditions, Swiss bond cleavage may also occur.

This example illustrates the reaction of a polyhydridosilane with an amine.
To a solution of 100 my of poly(phenylhydrido-Solon) (prepared as in EXAMPLE 1) in 1 ml of Tulane was added 50 micro liters of N-benzylmethylamine. Within minutes of reaction, spectroscopic analyses indicated the presence of Si-N(CH3)(CH~C6Hs) groups. Some Sigh bonds remained unrequited.

-29- ~39~

In this example a mixture of polyhydridosilane and polyvinyl compound were photo chemically cross linked.
150 my of poly(methylhydridosilane) (prepared as in EXAMPLE 2) was dissolved in 220 my of divinylbenzene.
The solution was stored at 20C in the dark for a week with no change. The sample was then placed under an ultraviolet lamp, and within 15 ho a hard, brittle resin had formed.

This example illustrates the reaction of polyhydridosilane containing a sill derivative of sodium with a transition metal halide.
Equivalent amounts of poly(phenylhydridosilane) containing a sill derivative of sodium (prepared as in Example 8) and cyclopentadienylirondicarbonyl bromide were placed in THY. Reaction was immediate, and spectroscopic analyses confirmed the presence of Si-Fe(C0)2(CsEIs) groups.

This example illustrates the reaction of a polyhydridosilane with an organometallic Periodic Group IA
compound.
150 my of poly(phenylhydridosilane) prepared as in EXAMPLE 1 was placed in 1.5 ml of THY. 0.5 ml of 2.5 M
n-butyl lithium in hexane (Aldrich Chemical Co., Milwaukee, WI) was added, and the reaction mixture immediately turned orange. Chemical and spectroscopic analyses indicated that reaction had occurred at both Sigh and Swiss bonds, and that Si-(C4EIg) and Swahili+ groups had formed.

This example illustrates the thermal treatment (pyrolyzes) of poly(hydridosilane) to pyropolymer.
The poly(hydridosilane) was sensitive to air and all operations with this polymer were conducted in a nitrogen atmosphere.

_30_ 2 3 6 Poly(hydridosilane), prepared as described in EXAMPLE 4, and protected by storage in nitrogen, was dissolved in dry, oxygen-free THY to give a solution (0.1 g of polymer in 1 g of THY). A few drops of this solution were placed on a sodium chloride (salt) plate, and the solvent was then removed under vacuum to give an adherent film having strong infrared (IT) adsorptions. The film (on the salt plate) was placed within a larger, nitrogen-filled infrared cell such as a gas cell to allow an IT spectrum of the film to be obtained. The IT showed absorption bands due to the Sigh and Sue groups. The film (on the salt plate) was placed in a quartz tube and heated under vacuum at 200C for one hour. Thereafter, this plate was allowed to cool, and its IT spectrum was taken (nitrogen atmosphere).
No significant change was noted in the IT spectrum.
After heating of the above film (on the salt plate) at 400C for one hour, the absorption bands had almost disappeared and had shifted to lower wavelengths.
After heating at 600C for one hour, the sample was black and infrared absorption bands were no longer visible.

This example illustrates the pyrolyzes of aliphatic, poly(methylhydridosilane) to a pyropolymer.
The conversion of the polysilanes to pyropolymers and ultimate ceramic products was monitored by vacuum pyrolyzes techniques. Poly(methylhydridosilane) (100 my, 2.27 moles), prepared as in EXAMPLE 2, was heated under vacuum at 10C Manuel with careful monitoring of the volatile products and visual observation of color change.
The non-condensable gases were removed continuously, collected in a Tippler pump, and the cumulative total for each 100C increment was recorded before analysis by mass spectrometer to determine the ratio of SUE (Table I).
Volatile compounds condensing in a liquid nitrogen trap were analyzed by infrared and mass spectrometer and the final ceramic residue (pyropolymer) was subjected to X-ray, ~239S~

Electron Spectroscopy for Chemical Analysis (ESCA), and Scanning Electron Microscopy (SUM) evaluation. By 430C the polysilane had become bright yellow with production of SHEA
(0.04 moles), Ho (0-03 moles), and Swiss (0.29 moles).
A clear colorless condensate, which collected just outside the hot zone of the furnace tube, had an IT spectrum identical to the starting polymer and was recorded as recovered oligomers and polymers.

TABLE I
PYROLYZES OF POLY(METHYLHY~RIDOSILA~E) Total Gas Temperature (moles) Composition (wit %) C Color each interval SHEA Ho 15430 Bright Yellow 0.06761 39 510 Buff 0.67342 58 600 Blue-black 0.58210 90 700 Lustrous grey-black0.189 12 88 800 Lustrous grey-black0.163 7 93 20910 Lustrous grey-black0.018 10 90 Summarizing, to indicate mass balance in moles:
910 o [Chosen > Ho + SUE + Swish + ceramic residue 252.27 -0.60 (recovered oligomer) 1.67 1.28 0.42 0.29 51.2 my (70 wit %) The above analysis figures imply that a significant amount of carbon, present as methyl groups in the starting polysilane, was eliminated as methane during the earlier stages of the pyrolyzes and that the resulting pyropolymer was likely to be correspondingly richer in silicon.
Although this pyropolymer was found to be largely amorphous, x-ray analysis showed three diffraction lines attributable to cubic silicon. The Claus) and Swoop) photoelectron spectra also revealed that elemental silicon ~2395~

was present, together with silicon bonded to carbon and a carbide form of carbon. Under the particular reaction conditions described in this example, more silicon was present as the element than as silicon carbide.

This example illustrates the pyrolyzes of aromatic poly(phenylhydridosilane) to a pyropolymer.
The techniques described in EXAMPLE 21, were also used to study the thermal decomposition of polyphenylhydridosilane, prepared as described in EXAMPLE
1. In this case the vowel products included phenylsilane, Bunsen and hydrogen. The polymer was again heated under vacuum and became bright yellow at 330C, darkened to amber at 560C and finally converted to a vitreous black ceramic pyropolymer at 910C.
Summarizing, with amount in moles:

(C6HsSiH)rl Bunsen and phenylsilane + hydrogen + black glass 80 my 16.5 my (0.70 mole) (0.76 mole) The black pyropolymer did not show an x-ray diffraction pattern. Thermolysis of this polymer was also followed thermogravimetrically, using the heating rate and nitrogen flow rate described in EXAMPLE 3. The weight loss curve was broadly similar to that of the copolymer with a maximum weight loss of 48 percent attained by 580C.

This example illustrates the pyrolyzes of poly(methylhydridosilane) in the presence of ammonia to form a silicon nitride-containing pyropolymer.
A 0.2 g sample of poly(methylhydridosilane) (see EXAMPLE 2) was heated under vacuum to 950C at 10C per minute, and this final temperature was maintained for 33~ 95~6 5 his. There was some loss of volatile products as described in detail in EXAMPLE 21. Without any exposure of the resultant pyropolymer to the atmosphere, an excess of pure gaseous ammonia was admitted to the evacuated chamber until a pressure of 10 cm of Hug was obtained. Heating was 5 continued at 950C for 5.5 hours. The resultant pyropolymer was cooled under vacuum and spectroscopic analysis confirmed the presence of silicon nitride, and its elemental analyses C2 gnu ooze 6 corresponded to a composition Seiko Sweeney.

Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope and spirit of this invention, and it should be understood that this invention is not to be unduly limited to the illustrative embodiments set forth herein.

Claims (27)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A polyhydridosilane having a catenated silicon backbone having an average of 15 to 4000 silicon atoms with a number of hydride atoms per silicon atom in the range of 0.3 to 2.2, at least 0.1 gram of said polyhydridosilane being soluble at 20°C in 100 grams of at least one of the organic solvents selected from the group consisting of tetrahydrofuran, toluene, and methylene chloride.

2. An organic solvent-soluble polymer having a backbone consisting essentially of repeating monomeric units having the formula wherein R is the same or different and is independently selected from the group consisting of 1) hydrogen, 2) a linear, branched, or cyclic aliphatic group having 1 to 10 carbon atoms and optionally containing at least one Periodic Group VA or VIA atom, 3) an aromatic group which is unsubstituted or substituted by up to three C1 to C10 linear, branched, or cyclic aliphatic groups, said aromatic or aliphatic groups optionally containing at least one Periodic Group VA or VIA atom, the total number of carbon atoms being up to 25, 4) a single bond connecting two silicon atoms, 5) a metal atom selected from the group consisting of Periodic Groups IA and IIA, and 6) an inorgano- and organometallic group comprising at least one Periodic Group IB to VIIB, VIII, Lanthanide or Actinide element, with the proviso that the ratio of hydride to silicon is in the range of 0.3 to 2.2: and the average number of monomeric units of said formula in the polymer is in the range of 15 to 4000.

3. The polymer according to Claim 2 wherein said monomeric units are randomly arranged.

4. The polymer according to Claim 2 wherein each R is independently selected from hydrogen, methyl, ethyl, phenyl, and a single bond connecting two silicon atoms.

5. The polymer according to Claim 2 having an average number in the range of 20 to 4000 units of the formula ?SiH0.3-2.2?.

6. The polymer according to Claim 2 which is selected from a random copolymer of a) a dialiphaticsilane and a dihydridosilane, and a random copolymer of b) an aliphatichydridosilane and an aromatichydridosilane.

7. The polymer according to Claim 2 selected from polymers comprising at least one monomeric unit selected from units having the formulae ?SiH2?, ?CH3SiH?, ?C6H5SiH?, and ?C2HsSiH?.

8. The polymer according to Claim 2 wherein R is selected from the group consisting of hydrogen, alkyl, alkoxy, alkylamino, aryl, arylamino, and a single bond connecting two silicon atoms, and combinations thereof.

9. The polymer according to Claim 2 wherein each R is independently selected from the group consisting of hydrogen, methyl, ethyl, n-butyl, methoxy, benzyl, benzylmethylamino, phenethyl, and a single bond connecting two silicon atoms.

10. The polymer according to Claim 2 further comprising at least one group selected from wherein R1 is selected from the group consisting of 1) hydrogen, 2) a linear, branched, or cyclic aliphatic group having 1 to 10 carbon atoms and optionally containing at least one catenary oxygen atom, 3) an aromatic group optionally substituted by up to three C1 to C10 linear, branched, or cyclic aliphatic groups, said aliphatic and aromatic groups optionally containing at least one catenary O atom, the total number of carbon atoms being up to 25, and 4) a single bond connecting two silicon atoms; and M is a Periodic Group IA or IIA metal.

11. The polymer according to Claim 10 wherein M
is selected from the group consisting of sodium and lithium.

12. The polymer according to Claim 2 which has been substantially crosslinked.

13. A method of preparing a polyhydridosilane having an average of 9 to 4000 silicon atoms and having a hydride to silicon ratio in the range of 0.3 to 2.2 comprising the steps of:
a. providing at least one hydridosilane having the formula (R1)2SiX2, wherein R1 is selected from the group consisting of 1) hydrogen, 2) a linear, branched, or cyclic aliphatic group having 1 to 10 carbon atoms and optionally containing at least one catenary O atom, 3) an aromatic group optionally sub-stituted by up to three C1 to C10 linear, branched, or cyclic aliphatic groups, said aliphatic and aromatic groups optionally containing at least one catenary O atom, the total number of carbon atoms being up to 25, and 4) a single bond connecting two silicon atoms;
X is a halogen atom, and b) reacting said at least one hydridosilane, in the presence of a catalytically effective amount of napthalene or other poly-nuclear aromatic compound, with a Periodic Group IA or Group IIA
metal or alloy in an amount of at least 1 equivalent of metal per equivalent of halogen in an inert atmosphere and in an inert diluent for a time sufficient to provide a polyhydridosilane, at least 0.1 gram of said polyhydridosilane being soluble in 100 grams of organic solvent at 20°C.

14. The method according to Claim 13 wherein said poly-hydridosilane comprises repeating monomeric units having the formula:

wherein R1 is as defined in Claim 13; and wherein the ratio of hydride to silicon is in the range of 0.3 to 2.2: and the average number of monomeric units in the polymer is in the range of 9 to 4000.

15. The method according to Claim 13 further comprising the step of reacting said resulting polyhydridosilane with a sufficient quantity of a Periodic Group IA or IIA
metal to provide a silyl derivative of a Group IA
or IIA metal having the formula wherein R1 is as defined in Claim 13, and M is a Periodic Group IA or IIA metal.

16. The method according to Claim 13 further comprising the step reacting said polyhydridosilane with a reagent selected from alcohols, amines, alkenes, aromatic or aliphatic halides having the formulas ROH, R2NH, R2C=CR2, R3C-X, respectively, and inorgano-or organometallic compounds, wherein R and X are as defined above.

17. The method according to Claim 16 further comprising the steps of:
a. treating said silyl derivative of a Group IA
or IIA metal with a compound selected from the group consisting of alcohol ROH, amine R2NH, alkene R2C=CR2, inorgano- or organometallic compound MR1, metal M, aliphatic or aromatic halide R3CX and transition metal halide TXnLm, wherein R1 and X are as defined above, R is the same or different and is independently selected from the group consisting of 1) hydrogen, 2) a linear, branched, or cyclic aliphatic group having 1 to 10 carbon atoms and optionally containing at least one Periodic Group VA or VIA atom, 3) an aromatic group which is unsubstituted or substituted by up to three C1 to C10 linear, branched, or cyclic aliphatic groups, said aromatic or aliphatic groups optionally containing at least one Periodic Group VA or VIA atom, the total number of carbon atoms being up to 25, 4) a single bond connecting two silicon atoms, 5) a metal atom selected from the group consisting of Periodic Groups IA and IIA, and 6) an inorgano-and organometallic group comprising at least one Periodic Group IB to VIIB, VIII, Lanthanide or Actinide element, T is selected from one or more of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe, Ru, Os Co, Rh, Ir, Ni, Pd, Pt, or Actinide or Lanthanide metal, M is a Periodic Group IA or IIA metal, L is independently selected from one or more of the following groups: 1) an aliphatic or aromatic group containing one or more carbon-to-carbon multiple bonds; 2) a group containing one or more Periodic Group VA atoms optionally substituted with up to 4 groups independently selected from aliphatic and aromatic groups and hydrogen atoms; or the Group VA atom or atoms may be part of an aromatic group, or the Group VA atom may be multiply bonded to carbon and optionally substituted with at least one aliphatic or aromatic group, 3) a group containing one or more Group VIA atoms optionally substituted by up to 5 groups independently selected from aliphatic and aromatic groups, or a hydrogen atom, or, the Group VIA atom(s) may be multiply bonded to carbon and optionally substituted with at least one aliphatic or aromatic group;
4) R1, where R1 is as defined above: 5) CO; and wherein M is selected depending on so as to achieve a stable compound, n is an integer from 1 to 5, and m is an integer from 1 to 6;
to provide a derivatized polyhydridosilane.

18. The method according to Claim 13 further comprising the step of:
subjecting said polyhydridosilane to pyrolysis over a temperature range of 200 to 2000°C in a vacuum or an inert atmosphere and optionally in the presence of a nitrogen-containing compound to provide a pyropolymer having at least one group selected from silicon, silicon carbide, silicon nitride and carbon.

19. The method according to Claim 17 further comprising the step of:
subjecting said polyhydridosilane to pyrolysis over a temperature range of 200 to 2000°C in a vacuum or an inert atmosphere and optionally in the presence of a nitrogen-containing compound to provide a pyropolymer having at least one group selected from silicon, silicon carbide, silicon nitride and carbon.

20. The method according to Claim 19 wherein said nitrogen source is selected from the group consisting of ammonia, nitrogen, hydrazine, methylamine, and ammonium halide.

21. The method according to Claim 20 wherein said nitrogen source is ammonia.

22. The method according to Claim 19 wherein said pyropolymer comprises elemental silicon.

23. The method according to Claim 19 wherein said pyropolymer comprises silicon carbide.

24. The method according to Claim 19 wherein said pyropolymer comprises elemental carbon.

25. The method according to Claim 19 wherein said pyropolymer comprises silicon nitride.

26. An article comprising the polymer according to Claim 2.

27. A film or fiber article comprising the polymer according to Claim 2.